CANNES – Sympathy for the underdog takes on a literal meaning in this lightly dystopian canine thriller from the Hungarian writer-director Kornel Mundruczo, showing in the Un Certain Regard section in Cannes. On wet-nosed face value, White God is an urban adventure yarn about a teenage girl searching for her beloved pet dog. Under its furry skin, an angry allegory for political and cultural tensions in contemporary Europe.

The premise of this Hungarian/German/Swedish co-production is solid, even if the execution feels a little slack and the running time too long. Production values are also strong, with some impressive technical elements, notably the highly-trained animal castmembers. Further festival play seems certain, with theatrical interest likely to be niche but with fairly broad appeal based on the universally marketable doggy angle.

Young big-screen newcomer Zsofia Psotta gives a confident, convincingly surly performance as 13-year-old Lili, a solitary only child in contemporary Budapest forced to move in with her ill-tempered father (Sandor Zsoter) when her mother takes a job abroad. But dad has little patience for Lili's best friend, a handsome and unusually smart mongrel named Hagen. With new political laws banning cross-breed dogs coming into force, Hagen cannot stay in the apartment long.

Cruelly dumped alongside an urban highway, Hagen begins his journey through Budapest's shady underworld. Sold into an illegal dog-fighting ring, he is trained to become a ruthless killing machine before escaping from his savage human captors. In a four-legged twist on Rise of the Planet of the Apes, Hagen then masterminds a mass breakout from the city dog pound, leading an army of fellow hounds on a roaring rampage of revenge against mankind. Lassie's come home -- and this time he's boiling mad.

According to Mundruczo, White God is intended as a statement of solidarity for marginal and oppressed people. There are certainly strong echoes of Nazi-style ethnic cleansing in his depiction of an intolerant society imposing harsh new laws against mongrels, an increasingly timely theme in the light of recent election gains by Hungary's neo-Nazi party Jobbik. Another anti-racist allusion is coded in the film's title, a play on Sam Fuller's cultish 1982 movie White Dog, about a vicious German Shepherd trained to attack dark-skinned people.

Most shot in jerky hand-held style, with a stridently percussive score pumping up every hint of tension, White God falls somewhere between a superior genre thriller and a Big Statement movie. But much of the overlong human subplot could be safely trimmed or cut, bringing the canine story into sharper focus. Mundruczo's choice to use real dogs over digital effects is commendable, but also dampens potential menace and horror.

This is particularly true in the tame dog-fighting scenes, which should have been grotesque but -- no pun intended -- lack bite. The two lovable mutts who play Hagen are ultimately too cute to be scary, more Paws than Jaws, leading to moments of unintended comedy that undermine the film's serious tone. But these are not fatal flaws in an otherwise admirably unorthodox and sporadically gripping shaggy dog story.